Process of treating electrolytic and similar solutions.



G; A. GABRIEL.

PROCESS OF TREATING ELECTROLYTIC AND SIMILAR SOLUTIONS I APPLIGATIONFILED MAY 31, 1907. I 959,730. Patented May 31,1910.

2 SHEETS-SHEET 1.

[WWW "Hi e. A. GABRIEL. PROUESS OI: TREATING ELEGTROLYTIG AND SIMILARSOLUTIONS.

APPLIOATION FILED MAY 81, 1907'.

959,730; Patented MayBl, 1910i 2 sums-81mm 2-.

ii 19' o WW9; 'gnoewto Ia.

. George/{Gabriel sums STATES PATENT curios.

snoaen A; GABRIEL, or NEW YORK, it. Y., assienon' ro! BLEACH -& GAUSTICrnoonss COMPANY, OF NEW, YORK, N. Y., A

CORPORATION or NEW YORK.

PROCESS OF TREATING ELECTROLYTIC AND SIMILARSOLUTIONS.

Specification of Letters Patent. I

Patented May 231, ram.

a ucauon'ruea May 31, mp7. .sernuno; 376,647.

To all whom it may concern: l Be it known that I, GEORGE A. GABRIEL,

a citizen of the United States, and a resi-' dent of the borough ofBrooklyn, inthe city and State of New 'York, have invented certain newandsuseful-lmprovements in Processes of TreatingElectrolytic and SimilarSolutions, of whichthe following is a full, clear, and completedisclosure.

This inventlon relates to processes .or

,methods of forming or purifying solutions of diiferent' saltsused inlarge quantities in liquid discharged from the cathode chamber,

the chemical arts, and is particularly ap-' plicable to the purificationand production of solutions used in'gelectrolytic cells, such as ofthel-largreares or vertical type, having the anode and "cathode chamberssep-' arated by adiaphragm for producing chlorin and caustic soda by theelectrolysis of brine. In electrolytic ,cells of this type,'theelectrolyte passes through the diaphragm owing to the action of theelectric current and the hydrostatic pressure of'thesanolyte andis-acted upon at the cathode. 'However, more anolyte passesthrough thediaphragm than is decomposed at the cathode andthe therefore,- ontainssome of the, active 'or undeoomposed electrolyte, which, if Enotcollected and separated sirom the "products of decom osition, would-bewasted. 7 ne ,of

the ob ects of my invention," therefore, is to separate -the activeelectrolyte discharged from the cathode chamberfrom the products,

of decomposition, so that the same may be returned to the anode-chamberof the cellin 'the form of pure electrolyte.

One feature of my mvention'h-as for its object theestablishing'ofcomplete cycles or circuits through whwh the solutionsused l may'be' continuously passed so that the impureor" partlyspent'solution may be succes- (sively treated ,-in;series of steps topurify or strengthen the same. and then immediately .be returned to theapparatus in which it used, while at thesame time the'bywproductsare-reduced to commercial substances in the form of solids or solutions.

- ,tioned that are" ofhighefiiciency, both as to IA further object of.my invention is to provide processes of the nature above menmaterialsemployed and the energy consumed, and also that lessen the; time andlabor which has heretofore beennecesmry in producing similar results.

t'rolyte,

These and other objects and features of my invention will be hereinaftermore fully set forth andiclaimed in'the accompanying 1 claims.

"solving the same in'the presence of heat and at the same timeconverting the remaining 1 products of decomposition into compounds,

such as carbonates which may precipitate the impurities of the raw ornew elec after which the impurities may be filtered out and theelectrolyte returned to the electrolytic cell or other ap Theconcentration is preferably accomplished by the use of suitableevaporators and by centrifugal separators or driers, the liquid thrownoff by the latter either being subsequently changed to a solid fo'rm orallowed to remain as a liquid, thereby constituting two diiferent formsof finished by-product.

with an acid which reacts upon'the remaining small amounts of theproducts of decom- 'paratus or process. for further decompo- 'sition ortreatment.

Afiter the electrolyte has been filtered to remove the precipitate, andbefore returning to the electrolytic cell or other apparatus, it ispreferably treated position which have been converted into carbonates,such as sodium carbonate, and neutralizes the latter, forming solutionsof salts which are not injurious to the further use of the brine, I v

p .In the use, bl? electrolytic cells-ibis desirable that theelectrhlyte may be continuously supplied tothe cellandalso that'theelse-- trolyte may I the operation of the cell, thereby obviating thenecessity of interrupting the ,electrolytic process for the purposeoi-replenishing or cleansing the fluid. When the process above outlinedis'fused for the-purpose of utilizing the discharge from the cathodechamber for purifying-and producing the liquid supplied to the anodechamber of an electrolytic cell, I'm'ay' combine the same with a rocesswhich is carried-out'in the circulating system with the anode" chamberof'the electrolytic cell. The action of the anolyte of the elegtrolyticcell upon the-anode-aml ether parts be continuously purified during iebwith which itcomcs in contact causes the anolyte to take up certainimpurities in the form of solids and gases which, if allowed to remainin the anolyte, impair its action. Briefly, this process of renewing andpurifying the anolyte comprises withdrawing the anolyte from the cell,passing the same through suitable bodies of the salt used in solution inthe anode chamber, filtering, freeing from entrained gases or air,mixing with additional quantities of the fresh anolyte and thatdecomposed, while the auxiliary cycle or circulation is of alargervolume and continuously, and rapidly purifies and strengthens theelectrolyte in the anode equal, at least, to the amount of the anolytethat has passed through the diaphragm or of the cell. The second processorseries of steps constitutes a cycle for the purification andstrengthening of the anolyte and is a continuous circulation of theliquid. From the-point at which the active purified electrolyteresulting from the first or main cycle or circulation is added to thesecond or auxiliary cycle or circulation, until the electrolyte entersthe anode chamber of the cell,

the two. cycles are preferably coincidentJ 'The main cycle of theprocess supplies the cellwithan amount of-the electrolyte equal to thatdischarged into the cathode chamber chamber.

For descriptions of different embodiments of my lnvention which'I deempreferable,

reference may be had to the following specification and to theaccompanying drawings forming a part thereof,-in which- Figure l is adiagram of essential steps of one formof my invention and alsoindicating the apparatus employed therewith, and -Flg. 2 is a slmilardiagram showing additional features of the process.

Referring to Fig. 1 the numeral 1 indicates an electrolytic cell oftheHargreaves or vertical' type fromwhich'the eflluentor partly Idecomposed electrolyte from the cathode chamber is discharged. In thecase of the electrolysis of I brine this eflluent contains caustic sodaand unused sodium chlorid' :The efliuentemerges from. the fcell 1 by thepipe 16 and is first passed through suitable vooncentrating apparatus,such as the 'evaporator 2 and the centrifugal separator or drier 3,which reduce the solution to the form of the salt of sodium chlorid,moistened with a slight amount of water, and traces of caustic soda.Thesalt is then dissolved in water with the addition of steam, forheating, and a suitable re agent, such as carbon dioxid, is also added.The carbon dioxid acts upon the remaining caustic soda or similar alkaliand produces sodium carbonate or other carbonates. This step ispreferably carried out in an agitator as indicated at a, whichthoroughly mixes the ingredients referred to with the solution of sodiumchlorid. When the liquid containing the sodium carbonate insolution,'together with the solution of sodium chlorid leaves theagitator, it has a specific gravity of about 2559B. It is stored in asuitable reservoir 5, where it is allowed to cool, and there becomessupersaturated. The sodium carbonate is then decomposed and produces aninsoluble salts which are precipitated. This precipitation is preferably"accomplished by adding to the solution suitable quantities offresh'brine from a source of Supply such as the reservoir 6, and whichusually contain impurities in the form of salts of calcium, magnesium,etc. salts act upon the sodium carbonate or similar substances producedby the conversion 'of the alkali, and form insoluble salts,-"such ascalcium carbonate, which are precipitated; The mixing of the brine withthe solu tion being treated andfthe precipitation of These theimpurities are preferably carried on in q a mixer indicated at 7. Themlxture is then passed through a filter,as indicated at '8, to free thesame from the precipitated matter. After passing through the filter asmall quantity of acid may be added to the mixture, and this is forthepurpose of neutralizing any excess alkali carbonate, there by convertingthe same into salts that are not'injurious to use in the electrolyticcell or other apparatus. The purified mixture or solution is then addedto the circulating cycle or system connected with the anode chambers ofthe electrolytic cell or cells.

This preferably comprises, first, heating the electrolyte to atemperature approximatw ing that of the anolyte, and is accomplishedbypassing the electrolyte through a coil placedin a tank of hot water orotherwise externally heated, as indicated at 9. After passing into theanode chamber and being acted upon by the electric current, theelectrolyte is then. withdrawn throughthe ipe l6 and passed through aplurality of filters such as indicated atxlO and 11, which filterscontain a quantity or layer of salt crystals whereby any weakening ofthe electrolyte may be compensated for. "The filter 11 is referably.provided with an outletpipe 26 'or the escape and'collection of gas Jenorator ".5.

trained in the electrolyte. -These filters remove any particles offoreign or solid mat- "ter and dirt which may be the result of theactionof the electrolyte upon the anode, firother parts of the electrolyticcell. electrolyte isthen conducted to,- and mixed with, theincom-i-nggbrine or electrolyte, the

circulation being aided suitable means," such as an air lift, asindicated at 12. All

tion 15 extending toward the bottom of.

the receptacle, and beneath which the liquid must .pass. Thefirst-compartment formed by; the partition 15 is provided with an airoutlet 25 throughwhich the air introduced by the air lift maybedischarged. In pass- .ing into the second compartment of thereceptaclc 14. any gas'contained in the electrolyte is allowed topa'ssoff through a connection with the pipe 26, and as the new or purifiedelectrolyte mixed with the brine is also conducted to this compartment,they both become mixed and then, continue on through the circulatingsystems.

The above'is one of the simplest embodiments of my invention, butcertain changes "or additions may be made therein, as indi' cated inFig. 2. In this embodiment of the invention, the automatic centrifugalseparator 17 is preferably provlded with two liquid discharge sections,from the lower one of which strong caustic soda wlthisome unused sodiumClllOIld' 1s discharged.

This is then carried to, a boat pan 18,

from which it is fed into suitable evaporating kettles 19. The productof these kettles ihcn forms one of the finished by-products, such ascaustic soda in solid form.

\Vatcr is added to the upper section of the cei'itrifugal separator 17,for washing the concentrated salts therein, and this watcr, containingsome salt in sohition and a slight amount of alkaline matter, such asthe caustic soda, is carried to a storage tank 20, into which theelii-uent of the cell preferably discharges before passing to the'evap-This washing solution is thereby returned to the main circuit of theprocess and then passes through the evaporator and the concentrator andis subjected to the steps of the process just described. I also preferto employ a second auton'iatic centritugal separator 21. This also hasupper and lower liquid discharge sections, the upper onemi which'issupplied with water for washing the crystals or solid matter beingtreated thereby. This washing water as discharged contains a slightamount of cans tic soda, together with a slight amount of soda, andinorder to convert this into a subsodi'umchlorid that has been dissolvedfrom. the crystals; in the separator, and .is then i also added to thestorage tank-20 and sub.- jected to-the concentrating steps of the proc-The discharge from the"lowe r sectionof the separator'21. is conductedtoa stor-' 'a'getank 22 and since said discharge con"- sists ofpractically pure "caustic soda, the

contents of the storage tank constitute-one form of commercial liquidby-product.

I The crystals or solid matter discharged by the centrifugals .17and-21, are carried to the agitator 4; and heated in a suitable mannersuch as by the introduction of steam, said steam also of courseproviding water which 89 dissolves the solid matte-r supplied to the Thecrystals added to thisagiagitator.

of caustic ta'tor also contain a small amountstance which may beprecipitated, I add a suitable reagent, such as carbon 'd-ioxid, whichacts upon the caustic soda producing sodic carbonate. The mixturethereby obtained, in this instance the solution-of salt which is heatedto a high temperature and therefore becomes supersaturated, togetherwith the sodic carbonate in solution, is conducted to a storage tank 5,in which the solution is allowed to cool. The remainder of the processis the same as before described in connection with Fig. 1; that istosay, thesodic carbonate precipitates the impurities of the new brine, inthe mixer '7. The mixture is then filtered and a slight amount of acidadded to neutralize whatever slight excess of sodicrarbonatemay remainin the mixture. The mixture orsol'ution .1 is then supplied to thecirculating system connected with the anode chambers of-thevelectrolytic cells as before described. .5

In using the term brine 1i wishto be understood as referring to asolution of any salt'that is used as. the principal substance to betreated in the process in conjunction withan electrolytic cell orotherapparatus or process.

I wish it to be understood that I do not consider the invention to belimited totheI exact details of arrangement, materials and procedureshown and described, for-the invention is applicable to the purificationof solutions used in other apparatus and processes and to solutions usedin-other'ty-pesof electrolytic cells.

Various modifications are also possible invention, what I claim anddesire to protect by Letters iatent is:

1. In an electrolytic process, in combination with the step ofelectrolysis, a continuous cycle of steps constituting a circulation-30fthe electrolyte, for supplying pure I30 electrolyte equal to thatdecomposed or dis charged and a cycle of steps constituting an auxiliarycirculation for purifying and strengthening the electrolyte, treating insaid cycle a greater volume than in the main cycle.

'2. In an electrolytic process, in combination with the step ofelectrolysis, a continuous cycle of steps constituting a circulation ofthe electrolyte 'and comprising, concentrating the same to solid form,dissolving, and introducingamounts of raw electrolyte, and a cycle ofsteps constituting an auxiliary circulation of such electrolyte in theform of an aqueous solution, and including the steps of purifying andstrengthening the same.

3. In anelectrolytic process, in combination with the step ofelectrolysis, a continuous cycle of steps constituting a circulation ofthe electrolyte and comprising concentrating the same to solid form,dissolving and introducing amounts of new electrolyte,

and a cycle of steps constituting an auxiliary circulation of theelectrolyte in the form of an aqueous solution andcomprising thestep ofaddingv quantities of the pure electrolyte.

4. In an electrolytic process, in combination with the stepofelectrolysis, a continuous cyclev of steps constituting a circulationof the electrolyte and comprising, concentrating and separating saidelectrolyte from the products of decomposition so that the same may beagainsubmitted to electrolysis,

and a cycle. of steps constituting an auxiliary circulation of theanolyte for purifying. and strengthening the. same.

5. In an electrolytic process, in combination with the step ofelectrolysis, a continuous cycle of steps'constituting a circulation andtreatment of the electrolyte for eliminating the products'ofdecomposition. and supplying pure electrolyte, and a cycle of stepsconstituting all-auxiliary circulation for purifying and strengtheningthe electrolyte, said cycles including the step of heating to thetemperature of the electrolyte maintained during electrolysis.

GQIn an electrolytic process, in combination with the step ofelectrolysis, a continuous cycle of steps constituting a circulation andtreatment-of the electrolyte for eliminating the products of.decomposition and supplying pure electrolyte, and a cycle of stepsconstituting an auxiliary circulation for purifying and strengtheningthe elec: trolyte, the last step of said cycles being the heating of theelectrolyte to its temperature during electrolysis;

7. In an electrolytic process, in combination with the step ofelectrolysis, a continuous cycle of steps constituting a circulation andtreatment of the electrolyte for supplying pure electrolyte, anda cycleof steps constituting an auxiliary circulation, comprising, the step ofremoving solid impurities, the step 'of removing entrained gases,

and the step of supplying additional quantities of pure electrolyte.

8. In an electrolytic process, in combination with the step ofelectrolysis, the process of treating the discharged electrolyteremaining in the catholyte, which comprises tion with the stepofelectrolysis, the process 7 of treating the discharged electrolyteremaining in the catholyte, which comprises removing the undecomposedelectrolyte associated with a predetermined amount of the product ofdecomposition, converting the said product of decompositionint-osubstances which purify the raw electrolyte, I

adding definite amounts of the raw electrolyte, and then submitting thepurified electrolyte to said step of electrolysis.

10. In an electrolytic.process,'in'combina tion with the stepofelectrolysis, the process of treating'the discharged catholytecontain- .ing the undecomposed electrolyte, which comprises, separatingout said electrolyte associated with a predetermined amount of theproduct of -decomposition, converting said product into a purifier forthe raw electrolyte, adding quantities of said raw electrolyte, and thensubmitting the liquid obtained to said step of electrolysis.

11. In an electrolytic process, in combination with the st( pofelectrolysis,"the process of treating the discharged productcontaining the original undecomposed electrolyte,

which comprises separating out said elec' trolyte associated with :a'predetermined amount of the product of decomposition, converting saidproduct into a substance which will precipitate the impurities of theraw electrolyte, adding quantities of said raw electrolyte, removing theprecipitate,

and then submitting the liquid obtained tosaid step of electrolysis.

12. In an electrolytic process,in combination with the step ofelectrolysis, the process of treating the discharged product containingthe originalundecomp sed electrolyte, which comprises, concentrating tosolid form and separating out the said electrolyte associated with asmall amount of-the product of decomposition, washing the same withwater, reconcentrating' said wash water, treating said concentratedelectrolyte and associated product to form a purifier for the rawelectrolyte, adding quantities of the raw electrolyte, and thensubmitting to said step of electrolysis.

13. In an electrolytic process, in combination with the step ofelectrolysis, the process of treating the discharged product containiiigthe original undeco-mposed electrolyte,

concentrating the said electrolyte to solid form, mechanicallyseparating said concentrated electrolyte associated With a small amountof the product of dewhich comprises,

' composition, washing the same, dissolving,

ciated with a small amount of the productconcentrating said electrooutsaid electrolyte assoof decomposition, said concentration and separationbeing eiiected in a plurality of similar successive steps and producingthe electrolyte as a solid after each step, dissolving the same, andthen submitting to said step of electrolysis.

15. In an electrolytic process in combination with the step ofelectrolysis, the process of treating the dischargedproductcontainingthe original undeoomposed electrolyte,

which comprises, separating out said electrolyte associated with a smallamount of the latter into a substance which product of decomposition,converting the may be used for precipitating, and then addmg a solutionI containing matter-to be precipitated.

16. In an electrolytic process in combination with the stepofelectrolysis, the process of treating the discharged product containing'the original undecomposed electrolyte, which comprises, separating-outsaid electrolyte associated with a small amount of the product ofdecomposition, precipitating thereby the impurities in the rawelectrolyte,

neutralizing any excess of the converted product of decomposition, andthen submitting to said step of electrolysis.

17. In an electrolytic process, in combination with the step ofelectrolysis the process of treating the discharged product containingthe original undecomposed electrolyte, which comprises, separating outsaid electrolyte associated witha small amount of the product ofdecomposition, precipitating, by'a suitable mixture thereof withreagents, the impurities in the raw electrolyte, adding a suitable acidto neutralize any excess of said reagents, and then submitting to saidstep of electrolysis.

18. In an'electrolytic process, tion with the step of electrolysis theprocess of treating the discharged product containing the originalundecomposed' electrolyte,

which comprises, separating out said elec-' trolyte associated with apredetermined amount of the product of decomposition, treating the samewith a gaseous reagent,

adding a supply of the raw electrolyte,-re-

undecomposed electrolyte,

in combinamoving the separated impurities thereby ob tained. and thensubmitting the purified electrolyte to said step of electrolysis.

19, In an electrolytic process in combination with the step ofelectrolysis, the process of treating the discharged product containingthe original undecomposed electrolyte, which comprises, separating outsaid electrolyte associated with a predetermined amount of the productof decomposition, heating to a predetermined temperature, treating witha gaseous reagent, adding a supply of the raw electrolyte, removing theseparated impurities thereby obtained, and then submitting the purifiedelectrolyte to said step of electrolysis.

20. In an electrolytic process in combination with the step ofelectrolysis, the process of treating the discharged product containingthe original undecomposed electrolyte, which comprises, separating outsaid electrolyte associated with a predetermined amount of the productof decomposition, treating with carbon dioxid, adding a sup ply of theraw electrolyte, removing the separated impurities thereby thensubmitting the purified electrolyte to said step of electrolysis.

21. The process of purifying an electrolyte discharged from a-cathodechamber, which comprises, separating out the undecomposed electrolyteassociated with a predetermined amount of the product of decomposition,converting said associated product of decomposition into a purifier forthe raw electrolyte, and adding a supply of said raw electrolyte. V

22. The process of purifying an electrolyte,which comprises, separatingthe undecomposed electrolyte'associated with a pre determined amount ofthe product of decomposition, converting said associated product ofdecomposition. into substances which will precipitate the impurities ofthe raw electrolyte, adding raw electrolyte, and removing theprecipitate by filtration.

23. The process of purifying an electrolyte which comprises, separatingundecomposed electrolyte associated with a predetermined amount of theproduct of decomposition, converting said'associated product ofdecomposition into substances which will precipitate the impurities ofthe raw electrolyte, adding raw electrolyte, removing the precipitate,and then neutralizing any excess of the converted product ofdecomposition. I

24. In-an electrolytic process, in. combination with a continuous maincirculation of chamber, for purifying and supplying the electrolyte, alocal or auxiliary circulation of the anolyte, including the steps ofelectrolys'is and filtering.

25. In an electrolyticprocess, in combinaobtained, and

the electrolyte discharged from a cathode tion with a continuous maincirculation of the electrolyte discharged from a cathode chamber, forpurifying and, supplying the electrolyte, a local or auxiliarycirculation of anolyte, including the steps of electrolysis, filtering,and extracting the entrained gases.

26. In an electrolytic process, in combination with a continuous maincirculation of the electrolyte discharged from a cathode chamber, forpurifying and supplying the electrolyte, a. local or auxiliarycirculation of the'anolyte, including thejsteps-of-electrolysis, passingthrough crystals of the anolyte, and filtering;

27. In an electrolytic process, in combination with a continuous maincirculation of h the electrolyte discharged from" a cathode chamber, forpurifying and supplying the electrolyte, alocal or auxiliary circulationof the'anolyte, including the steps of electrolysis, passing throughcrystals of the 'fanolyte, filtering, extracting the entrained gases,and heating: a

28. The process of treating solutions discharged from the cathodechambers of electrolytic cells, which comprises removing theunde'composed electrolyte associated with a small amount of the productof decomposi-- tion, converting'the latter'into a purifier forelectrodes. I a

the raw electrolyte, adding such raw elec-' trolyte, removingthe-separated impurities, subjectingthe resulting electrolyte to theactionof theelectrodes, replenishing with a suitable salt, filtering,addlng fresh electrolyte, and then submitting to the action of the -29.The process of treating electrolytes V which comprises, subjecting thesame to the actionof electrolysis in the anode chamber,-

withdrawing the anolyte, replenishing the same with asuitable salt,filtering, addingfresh quantities oi the anolyte. equal to a i theelectrolyte discharged (ii-"decomposed,

and again submitting the "sael te to electrolysis, y

30. The process oftr'eating: electrolytes which comprises, subjectingthe sameto the action of electrolysis in the anode chamber,

withdrawing the anolyte, replen shingand' lyte to electrolysis.

purifyingthe same,adding fresh quantities of the anolyteequal to theelectrolyte dis-v charged' or decomposed, and again, sub

mitting-the anolyte, to electrolysis. 31. The process of treatingelectrolyte which'comprises, heatingthe same, subject-'- ing the same tothe action of electrolysis in the anode chamber, withdrawing the ano- Ylyte, replenishing and purifying the same,

adding fresh quantities of theanolyte equal tothe electrolyte dischargedor decomposed,

and again submitting the anolyte toelectrolysis. v 132. The process oftreating electrolytes whichcomprises, heating the .same,s'1;1 bjecting'the same toithe'action of electrolysis in the anode chamber,withdrawing the anosalt, filtering, adding fresh quantities of theanolyte equal to the electrolyte discharged or decomposed, heating, andagain submitting the anolyte to electrolysis.

33. The process, of treating electrolytes which comprises, heating thesame, subjecting the same, to the action of electrolysis in the anodechamber, withdrawing the anoly te, replenishing and filtering thesame,

- cooling,-changing the effective specific gravlyte, replenishing thesame with a suitable in the anode chamber, withdrawingtheanolytereplenishing the s h v u ble. salt, filtering, introducing airfor changing the efiective'ispecific gravity, removing said air-,-removin fresh quantities of the anolyte equal to the electrolytedischarged or decomposed by athe entrained gases, adding cell, heating,and again submitting the ano- GEORGE A. GABRIEL. -Witnesses:

WALTER S. JONES, EDWARD W.- .VAILL, -J r.

